Yes you should. Remind them there had been a programme to upgrade all Vado BLOKS users to TCD-W, and many users got the conversion as the post-warranty service. Also mention, you are ready to cover the labour. They might politely turn down your request or show Specialized is the company that really cares. It won't hurt for sure! If you succeed, your Vado would become a 2020 model, and you'd be delighted with the performance and freedom of Mission Control!
If you need yet another powerful but heavy Turbo e-bike that's fine. After I got my Vado 6.0 upgraded to TCD-w, I chose a Vado SL as my another Specialized e-bike for a completely different riding experience!